High-strength, lightweight blow-molded plastic structures

ABSTRACT

Blow molded plastic structures are provided for use in various structures such as, but not limited to, tables, chairs, walls, backboards, storage bins, sports equipment and the like. The blow molded plastic structure has a first surface and a second surface extending between a first end and a second end and forming a chamber there between. A plurality of depressions is formed on the second surface and extends into the chamber. The depressions are usually unitary structures formed by a depression wall. Generally, the steeper the depression wall, the more strength is provided to the structure. In addition, where the plurality of depressions has a low profile and a greater density, increased strength is provided to the structure. The depressions may or may not be joined to the first surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part application of U.S. patentapplication Ser. No. 10/409,000, filed Apr. 8, 2003, now U.S. Pat. No.7,069,865, and entitled “High Strength, Light Weight, Blow-moldedPlastic Structures,” which, in turn claims priority to and benefit ofU.S. Provisional Patent Application Ser. No. 60/371,486, entitled“Utility Table with Blow-Molded Table top,” which was filed on Apr. 9,2002, both of which applications are hereby incorporated by reference intheir entireties.

BACKGROUND OF INVENTION

1. Field of Invention

The present invention generally relates to structures constructed fromblow-molded plastic and, in particular, to high-strength, lightweightblow-molded plastic structures.

2. Description of Related Art

It is known to construct various objects and items, such as tables,chairs, partitions, walls, and sports equipment, from plastic. It isalso known to construct some of these and other objects from blow-moldedplastic. As known to one of ordinary skill in the art, blow-moldedplastic structures typically include opposing surfaces or outer wallsthat enclose a hollow interior space. Because blow-molded structuresinclude a hollow interior space, many blow-molded structures are nothigh-strength. In fact, many known blow-molded structures are relativelylow-strength and are unable to support a relatively large amount ofweight or force.

In order to increase the strength of conventional blow-molded plasticstructures, it is known to attach strengthening ribs to the structures.For example, tables with table tops constructed from blow-molded plasticmay include strengthening ribs connected to the underside of the tabletop in an attempt to increase the strength of the table top. Thestrengthening ribs are often constructed from metal because metal ribsare relatively high strength. Disadvantageously, the metal ribs arefrequently attached to the table top by mechanical fasteners such asbolts or screws. The bolts or screws typically require holes in thetable top, which may create stress concentrations and/or potentialfailure points in the table top. The metal ribs may also be attached tothe table top by adhesives, but the adhesives may also decrease thestructural integrity of the table top and make the table top verydifficult to repair or replace. In addition, the metal ribs increase thenumber of components required to construct the table and increase thetime required to manufacture the table. Thus, while it is known to usemetal ribs to increase the strength of a blow-molded table top, metalribs undesirably increase the time and costs to manufacture the table.Further, the attachment of the metal ribs to the table top may decreasethe strength and/or structural integrity of the table top, and increasethe potential causes of failure of the table.

Conventional table tops constructed from blow-molded plastic may alsoinclude strengthening ribs or beams that are integrally formed in thetable top. For example, strengthening ribs may be formed in theunderside of the center of the table top in an effort to prevent saggingof the center portion of the table top. These strengthening ribs aregenerally large, elongated portions that extend along the length orwidth of the table top. The strengthening ribs may increase the overallstrength or structural integrity of the table top, but the ribs requirethicker outer walls so that the large, elongated ribs are correctlyformed in the table top. The large strengthening ribs may also requirethicker outer walls so that the ribs do not undesirably sag or deformduring the manufacturing process. Disadvantageously, the thicker outerwalls of the ribs may require additional plastic materials be used tocreate the table tops, which increases the costs and weight of the tabletops. In addition, the thicker outer walls may retain more heat duringthe manufacturing process. Thus, a longer cooling time may be requiredduring the manufacturing process in order to allow the thicker outerwalls to cool. This undesirably increases the time of the manufacturingprocess because the blow-molded table tops cannot be removed from themold until the tops are sufficiently cooled.

Known table tops constructed from blow-molded plastic may includeseveral large strengthening ribs to strengthen various portions of thetable top. For example, strengthening ribs may be placed near opposingends of the table top in order to increase the strength of the ends ofthe table top. Additionally, as discussed above, strengthening ribs maybe placed near the center of the table top to help prevent the table topfrom undesirably bending and to allow the table top to supportadditional weight. These strengthening ribs often protrude downwardlyfrom the underside of the table top and the ribs often have largeprofiles to create relatively strong supporting structures.Disadvantageously, the large, protruding ribs may undesirably decreasethe amount of room underneath the table top and limit the potentialdesign considerations for the table top.

Conventional table tops constructed from blow-molded plastic andincluding strengthening ribs may still not have sufficient strength andmay allow a portion of the table top to sag. In order to increase thestrength of these conventional table tops constructed from blow-moldedplastic, it is known to increase the number of ribs. These additionalribs, however, may require a larger area on the underside of the tabletop, which may limit the area that other features may be formed in thetable top. The plurality of strengthening ribs may also interfere withother desired features or components of the table, such as interferingwith the folding of the table legs into a collapsed position. The ribsmay also further increase the cooling time and manufacturing time of thetable top.

Additionally, while the large strengthening ribs may prevent largeportions of the table top from sagging, the ribs may allow smaller,localized portions of the table top to sag or deform. In particular,because the distance between the table top and the bottom portion of therib is greater than the distance between the upper and lower surfaces ofthe table top, this may allow localized portions of the table top tosag. Additionally, because the strengthening ribs are large and have anelongated length, they support the localized portion of the table topdifferently than the other portions of the table top. Thus, the uppersurface of the table top may be uneven because different portions of thetable top are supported differently. Further, because different portionsof the table top may be supported differently, various portions of thetable top may be supported differently, various portions of the tabletop may appear differently and/or be able to support a different amountof force or load.

BRIEF SUMMARY OF INVENTION

A need therefore exists for structures constructed from blow-moldedplastic that eliminates the above-described disadvantages and problems.

One aspect is blow-molded plastic structures that may have increasedstrength. Preferably the increased strength blow-molded plasticstructures are also lightweight.

Another aspect is blow-molded plastic structures that may include twoopposing surfaces. The two opposing surfaces are preferably separated bya generally constant distance. One of the opposing surfaces may begenerally planar and the other surface may include a plurality ofdepressions that are sized and configured to increase the strength ofthe blow-molded structure. The depressions may cover only a portion ofthe surface, substantially all of the surface, or the entire surface.The depressions preferably extend from one surface towards anothersurface and the ends of the depressions may contact the other surfaceand/or be spaced apart from the other surface.

Yet another aspect is the blow-molded plastic structures may be used tocreate a wide variety of items and objects such tables, chairs, walls,storage bins, sports equipment and the like. In particular, structuressuch as tables and basketball backboards may be constructed fromblow-molded plastic. Desirably, the upper surface of the tables and thefront surface of the backboards are generally planar, while the bottomor rear surfaces include a plurality of depressions.

Still another aspect is blow-molded plastic structures, in which thedistance between the depressions formed in the blow-molded structuresmay be substantially decreased, which may substantially increase thenumber of depressions formed in the blow-molded structure. This increasein the number of depressions formed in the blow-molded structure atfirst appears to increase the amount of plastic material required toconstruct the structure because of the increased surface area and numberof depressions. The increased number of depressions with the increasedamount of plastic also appears to increase the time required to cool thestructure during the manufacturing process. In particular, the increasedamount of plastic may retain more heat which would require a longercooling time before the structure could be removed from the mold. Thiswould increase the cycle time required to construct the blow-moldedstructures because the structures could not be removed as quickly fromthe mold. The increased number of depressions and closer spacing of thedepressions, however, allows the blow-molded structure to be constructedwith thinner plastic outer walls. Thus, contrary to conventionalblow-molded structures, increasing the number of depressions allowsblow-molded structures with thinner walls to be constructed.

Another aspect is blow-molded plastic structures constructed with anincreased number of depressions and thinner outer walls allow lessplastic to be used to construct the structure. The reduced amount ofplastic advantageously saves materials and resources. In addition, thecosts of the blow-molded plastic structure may be decreased because lessplastic is required.

A further aspect is blow-molded plastic structures constructed with anincreased number of depressions and thinner outer walls may result inless plastic being used to construct the structures. Advantageously,this may allow the weight of blow-molded plastic structures to bereduced. Thus, lightweight blow-molded plastic structures may beconstructed.

A still further aspect is blow-molded plastic structures is the thinnerouter walls allow heat to be dissipated more quickly during themanufacturing process, the blow-molded plastic structures to be cooledmore quickly. This may allow, for example, structures to be removedsooner from the mold. Additionally, because the increased number ofdepressions may provide more support for opposing surfaces, thestructures may be removed from the mold at higher temperatures.Accordingly, the manufacturing time and/or cycle time required toconstruct the blow-molded structures may be reduced, which may increasethe output and/or efficiency of the blow-molding process.

Yet another aspect is blow-molded plastic structures may be constructedwithout requiring conventional reinforcing ribs and beams. In fact,reinforcing ribs or beams are desirably not formed in the blow-moldedstructures because the ribs may require thicker outer walls and increasethe time of the manufacturing process. Further, the reinforcing ribs mayundesirably interfere with other structures or features formed in thetable top.

A further aspect is blow-molded plastic structures that may includedepressions that are preferably uniformly spaced to create generallyconsistent and/or standardized arrangements. A consistent arrangement ofdepressions may help create a structure with uniform characteristics.For example, a generally constant pattern of depressions may create astructure with generally uniform strength and structural integrity.

Another aspect is blow-molded plastic structures that may have a lowerprofile because reinforcing ribs are not required. Thus, the height orthickness of the blow-molded structures may be decreased.

Still another aspect is blow-molded plastic structures that may beconstructed with generally planar surfaces. In particular, blow-moldedstructures with large generally planar surfaces for articles such astables and basketball backboards may be constructed. Desirably, theclosely spaced depressions may allow large planar surfaces to be createdthat do not include significant sags, ripples or uneven surfaces.

Yet another aspect is blow-molded plastic structures that may includedepressions that are formed in one surface and extend towards anopposing surface. Advantageously, one or more ends of the depressionsmay contact the opposing surface. One or more ends of the depressionsmay also be spaced apart from the opposing surface. Significantly, ifthe ends of the depressions are spaced apart from the opposing surface,that may prevent visible marks and/or surface imperfections from beingformed in the opposing surface. This may also allow the opposing surfaceto flex or bend slightly if a load or force is applied to the surface.This may allow, for instance, the opposing surface to flex or bend untilit contacts the ends of the depressions. Significantly, this may allow achair back and/or chair seat to be constructed with increasedflexibility and/or comfort.

These and other aspects, features and advantages of the presentinvention will become more fully apparent from the following detaileddescription of preferred embodiments and appended claims.

BRIEF DESCRIPTION OF DRAWINGS

The appended drawings contain figures of preferred embodiments tofurther clarify the above and other aspects, advantages and features ofthe present invention. It will be appreciated that these drawings depictonly preferred embodiments of the invention and are not intended tolimits its scope. The invention will be described and explained withadditional specificity and detail through the use of the accompanyingdrawings in which:

FIG. 1 is an upper perspective view of an exemplary embodiment of ablow-molded plastic structure, illustrating a table with a blow-moldedplastic table top;

FIG. 2 is an exploded, bottom perspective view of the table shown inFIG. 1, illustrating the frame and legs detached from the table top;

FIG. 3 is a perspective view of another exemplary embodiment of aportion of a blow-molded plastic structure, illustrating a portion of ablow-molded plastic table top;

FIG. 4 is a perspective view of yet another exemplary embodiment of aportion of a blow-molded plastic structure, illustrating a portion of ablow-molded plastic table top;

FIG. 5 is a cross-sectional side view of still another exemplaryembodiment of a blow-molded plastic structure, illustrating an end ofthe depressions contacting an opposing surface;

FIG. 5A is a cross-sectional side view of a still further exemplaryembodiment of a blow-molded plastic structure, illustrating an end ofthe depressions adjacent to an opposing surface;

FIG. 6 is a cross-sectional side view of a further exemplary embodimentof a blow-molded plastic structure, illustrating an end of thedepressions spaced apart from an opposing surface;

FIG. 6A is a cross-sectional side view of the blow-molded plasticstructure shown in FIG. 6, illustrating a force applied to thestructure;

FIG. 7 is a bottom view of another exemplary embodiment of a blow-moldedplastic structures, illustrating a table top constructed fromblow-molded plastic;

FIG. 8 is a rear view of another exemplary embodiment of a blow-moldedplastic structure, illustrating a basketball backboard frame constructedfrom blow-molded plastic; and

FIG. 9 is a cross-sectional side view of yet another exemplaryembodiment of a blow-molded plastic structure, illustrating depressionsformed in opposing surfaces of the blow-molded plastic structure.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENT

This invention is generally directed towards blow-molded plasticstructures that have increased strength and/or are lighter weight. Theprinciples of the present invention, however, are not limited toblow-molded plastic structures with increased strength and lighterweight. It will be understood that, in light of the present disclosure,blow-molded structures which are disclosed herein can be successfullyused in connection with other types of blow-molded plastic structuresthat do not have increased strength or lighter weight.

Additionally, to assist in the description of the blow-molded plasticstructures, words such as top, bottom, front, rear, right and left areused to describe the accompanying figures. It will be appreciated,however, that the blow-molded plastic structures can be located in avariety of desired positions—including various angles, sideways and evenupside down. A detailed description of blow-molded structures that mayhave increased strength and/or are lighter weight now follows.

As seen in FIG. 1, a table 10 with a table top 12 constructed fromblow-molded plastic is one exemplary embodiment of a blow-molded plasticstructure that may be constructed with increased strength and/or lighterweight. It will be appreciated, however, that a wide variety ofblow-molded plastic structures may have increased strength and/orlighter weight, including, for example, tables, chairs, walls,partitions, basketball backboards, storage bins, sporting equipment, andthe like. Thus, while the table tops shown in FIGS. 1–7 and thebasketball backboard shown in FIG. 8 are examples of blow-molded plasticstructures that may have increased strength and/or lighter weight, oneskilled in the art will appreciate that other blow-molded plasticstructures with increased strength and/or lighter weight may beconstructed.

As shown in FIGS. 1 and 2, the table top 12 includes a first end 13, anupper or working surface 14, a second end 15, and a lower or mountingsurface 16. The table top 12 is supported by a first support pedestal orleg 18 and a second support pedestal or leg 20. A hollow, interiorchamber 17 is disposed between the upper surface 14 and the lowersurface 16 of the table top 12. It will be appreciated that the hollowinterior chamber 17 may include one or more structures disposed withinthe chamber such that it is generally hollow or the chamber may becompletely hollow.

The first and second legs 18, 20 are preferably movable between a firstposition in which the legs extend outwardly from the table top 12 asshown in FIG. 1 and a second collapsed or storage position in which thelegs are positioned near and generally parallel to the lower surface 16of the table top. In greater detail, the first and second legs 18, 20may each include a first end 22 that is connected to the table top 12and/or a frame 40 to allow the legs to be moved between the first andsecond positions. One skilled in the art will appreciate that the legs18, 20 may be movable relative to the table top 12 by other suitablestructures and/or methods.

Additionally, a first support brace 24 may be connected to the first leg18 and a second support brace 30 may be connected to the second leg 20.The first support brace 24 may have a proximal end 26 attached to firstleg 18 and a distal end 28 attached to a cross bar 36. Similarly, thesecond support brace 30 may have a proximal end 32 connected to thesecond leg 20 and a distal end 34 attached to the cross bar 36. Thecross bar 36 may be connected to the table top 12 and/or the frame 40.As shown in FIG. 2, the distal end 28 of the first support brace 24 maybe disposed next to or it may abut the distal end 34 of the secondsupport brace 30. The first and second support braces 24, 30 may beused, for example, to maintain the legs 18, 20 in the first position.

As shown in FIG. 2, the frame 40 may include a first side rail 42 and anopposing second side rail 44. Preferably, the first side rail 42 isdisposed substantially parallel to the second side rail 44, and the siderails preferably extend generally along the length of the table top 12.The length and configuration of the side rails 42, 44 may depend, forexample, upon the length and configuration of the table top 12. Inaddition, the side rails 42, 44 may extend only a portion of the lengthof the table top 12. The side rails may include one or more apertures 46that are sized and configured to facilitate attachment of the legs 18,20 and/or the cross bar 36 to the frame 40. The frame 40 may alsoinclude a first end rail 54 and an opposing second end rail 56 ifdesired. The end rails 54, 56 may include tab members 66 that are sizedand configured to allow the end rails to be attached to the side rails42, 44. Advantageously, the side rails 42, 44 of the frame 40 may helpprevent bowing, twisting, or deformation of table top 12, but it will beappreciated that table 10 does not require the use of a frame, siderails and/or end rails.

The frame 40 may be attached to a downwardly extending lip 48 locatednear the outer periphery of the table top 12. For example, the frame 40may be attached to an inner surface of the downwardly extending lip 48by one or more fasteners. It will be understood that other suitablemeans or methods for attaching the frame 40 to the table top 12 may beemployed, including, but not limited to, rivets, screws, bolts, glues,epoxies or other bonding materials. The height of the inner surface ofthe lip 48 is preferably generally equal to or greater than the heightof the frame 40 so that the frame is generally hidden from view when thetable 10 is viewed from a plane generally aligned with the upper surface14 of the table top 12. Advantageously, because the frame 40 may becompletely or generally hidden from view, the frame does not have to befinished and it may contain visible imperfections or flaws. In addition,because the frame 40 may be completely or generally hidden from view bythe lip 48, a more aesthetically pleasing table 10 may be created. Thelip 48 may also hide all or a portion of pivotal connection of the legs18, 20 to the table top 12. It will be appreciated, however, that thelip 48 does not have to hide all or a portion of the frame 40 or thepivotal connection of the legs 18, 20 to the table top 12.

The connection of the frame 40 to the table top 12 may also be hiddenfrom view by the lip 48. For example, as discussed above, one or morefasteners may be used to connect the frame 40 to the table top 12.Because the fasteners desirably extend only through the frame 40 and theinner surface of the lip 48 and not the outer surface of the lip, thefasteners are preferably not visible when the table 10 is viewed from aplane that is generally aligned with or above the table top 12.

Advantageously, because the frame 40 can be attached to the lip 48, noscrews or bolts have to be attached to the bottom surface 16 of thetable top 12. Because no holes have to be drilled or formed in thebottom surface 16 of the table top 12, no stress concentrations orfailure points are formed in the table top 12. Thus, the strength andstructural integrity of the table top 12 is not compromised by creatingholes in the table top. In addition, because the frame 40 is preferablynot bonded to the bottom surface of table top 12, the table top is notweakened or damaged by adhesive. Thus, strength and integrity of thetable top 12 may be retained because the frame 40 is not screwed, boltedor bonded directly to bottom surface 16 of the table top. Further, theattachment of the frame 40 to the lip 58 may reduce the stresses imposedon the bottom surface 16 of the table top 12, which may reduce thelikelihood of deformation or damage to the table top. One of ordinaryskill in the art will appreciate that the frame 40 could be attached toany suitable portion of the table top 12 and the table 10 does notrequire the frame.

As shown in FIGS. 1 and 2, the lip 48 is disposed about the periphery ofthe table top 12 and it may form at least part of an outer edge orboundary of table top. It will be appreciated that the lip 48 does nothave to create the outer edge or boundary of the table top 12 and thelip can extend around all or only a portion of table top 12. The lip 48is preferably integrally formed with the table top 12 during ablow-molded process to create a unitary, one-piece structure. It will beunderstood that the table top 12 and the lip 48 may also be formed fromtwo or more pieces that are subsequently attached by any suitablemechanism or method such as fasteners, adhesives, and like. It will alsobe understood that the table top 12 does not require the lip 48.

FIGS. 1 and 2 also show that the side rails 42, 44 of the frame 40preferably having a generally S-shaped cross section with a main bodyportion and two outwardly extending flanges. One flange is preferablypositioned proximate the lower portion of lip 48 and the other flange ispreferably positioned proximate the bottom surface 16 of table top 12.It will be appreciated that the flanges may either contact or be spacedapart from the lower portion of the lip 48 and/or the bottom surface 16of the table top 12, respectively, as desired. When the main bodyportion of the side rails 42, 44 is spaced apart from lip 48, a channel52 is located between the side rails and the lip. It will be understoodthat the frame 40, side rails 42, 44 and lip 48 may have other suitableconfigurations and arrangements depending, for example, upon theintended size and use of the table 10. In particular, the frame 40, siderails 42, 44 and lip 48 may have other configurations and arrangementsif the table top 12 is in the form of a circle, polygon, square,triangle, or any other suitable geometrical configuration.

As discussed above, the legs 18, 20 may be connected to the frame 40. Asbest seen in FIG. 2, each leg 18, 20 includes a pair of generallyparallel members 80 with a first end 82 and a second end 84. The firstend 82 of each generally parallel member 80 is secured to a cross bar 86that is sized and configured to be positioned within opposing apertures46 in the side rails 42, 44 of the frame 40. The cross bars 86preferably rotate within the apertures 46 when the legs 18, 20 are movedbetween the collapsed position and the extended position. In oneembodiment, a connector 90 is preferably disposed between respectivepairs of the generally parallel members 80 to assist in maintaining thedesired relationship of the generally parallel members.

It will be appreciated that the legs 18, 20 may be configured in avariety of ways and the legs may have other suitable designs, shapes andsizes. For example, the legs 18, 20 may include only a single elongatedmember or multiple elongated members, and the legs may be constructed asa single component or multiple components that are connected together.It will further be appreciated that the legs 18, 20 need not be inpivotal engagement with table top 12 to be collapsible. For example, thelegs 18, 20 may be detachably connected to the table top 12 such thatwhen it is desired to collapse the table 10 for storage, the legs aredetached from the table top.

As discussed above, the support braces 24, 30 are connected to the legs18, 20 and the table top 12. Preferably, the proximal ends 26, 32 of thesupport braces 24, 30 include a pair of arms 100 to facilitateattachment to the generally parallel members 80 of the legs 18, 20. Itwill be appreciated, however, that the legs 18, 20 and the supportbraces 24, 30 may have any suitable configuration and arrangementdepending, for example, upon the size and intended use of the table 10.The support braces 24, 30 may also include a locking collar or ring 108that is slidably disposed on at least a portion of the support brace.The locking collar 108 is preferably sized and configured to fit overoverlapping portions 102 and 104 of the support braces 24, 30 when thelegs 18, 20 are in the extended position. Advantageously, the lockingcollar 108 may be used to secure the legs 18, 20 in the extendedposition. It will be understood that other mechanisms may be utilized tolock the legs 18, 20 in the extended position.

As best shown in FIGS. 1 and 2, the distal ends 28, 34 of each supportbrace 24, 30 is connected to the cross bar 36. In one embodiment, thedistal ends 28, 34 of each support brace 24, 30, respectively, mayinclude an opening 142 to allow the support brace 24, 30 to be pivotallyconnected to the cross bar 36. The cross bar 36 may provide structuralsupport to the center of table top 12 and the cross bar may be connectedto the frame 40. It will be appreciated that the cross bar 36 does nothave to be connected to the frame 40 and a variety of other suitablemechanisms may be used to connect the distal ends 28, 34 of the supportbraces 24, 30 to the table top 12.

Tables with other suitable features and configurations are disclosed inAssignee's U.S. Pat. No. 6,112,674, entitled Portable Folding UtilityTable with Center Support Assembly; U.S. Pat. No. 6,431,092, entitledPortable Folding Utility Table with Center Support and Off-Set SupportLegs; U.S. Pat. No. 6,508,184, entitled Lightweight Folding Table withSelf-Fixturing Leg Attachment; U.S. Pat. No. 6,550,404, entitledPortable Folding Utility Table with Integral Table Top and Lip; U.S.Pat. No. 6,355,301, entitled Portable Folding Utility Table with FrameFastened to Inner Surface of Lip; and pending U.S. patent applicationSer. No. 10/216,342, entitled Table with Blow-Molded Top and PivotallyAttached Legs, filed on Aug. 10, 2002; and pending U.S. patentapplication Ser. No. 10/340,018, entitled Personal Table, filed on Jan.9, 2003. Each of the patent and applications are incorporated byreference in their entireties.

The table top 12 may include a number of features that facilitateattachment of the legs 18, 20, the cross bar 36 and the frame 40 to thetable top. For example, the table top 12 may include mounting members148 and securing members 152 that are preferably integrally formed inthe table top as part of a unitary, one-piece structure. Preferredembodiments of suitable mounting members and securing members aredisclosed in Assignee's U.S. Pat. No. 6,530,331, entitled PortableFolding Utility Table with Integral Receiving Members, which isincorporated by reference in its entirety.

As best seen in FIGS. 2 through 7, the bottom surface 16 of table top 12includes a plurality of depressions 200 that are preferably sized andconfigured to increase the strength and structural integrity of thetable top. The depressions 200 are preferably formed in the bottomsurface 16 of the table top 12 and the depressions extend towards theupper surface 14 of the table top. As discussed in more detail below,the ends of the depressions 200 may contact or engage the upper surface14 of the table top 12, or the ends of the depressions may be spacedfrom the upper surface of the table top. As shown in the accompanyingfigures, the depressions 200 preferably cover substantially the entirebottom surface 16 of the table top, but it will be appreciated that thedepressions may cover only a portion of the table top. Additionally,while the depressions 200 are shown and described as being located inthe bottom surface 16 of the table top 12, the depressions could beformed in any desired portion of the table top.

The depressions 200 are preferably arranged into a predetermined patternor array in order to increase the strength and structural integrity ofthe table top 12. In particular, the depressions 200 are preferablyspaced closely together and the depressions cover substantially theentire bottom surface 16 of the table top 12. Advantageously, closelyspacing the depressions 200 over substantially the entire bottom surface16 allows a table top 12 with increased strength to be constructed. Inaddition, it eliminates the elongated ribs and beams that were requiredin many conventional structures constructed from blow-molded plastic.

As shown in FIGS. 3 and 4, the depressions 200 are desirably formed inan array. As shown in FIG. 3, one row 202 of depressions 200 may bestaggered with respect to an adjacent row of depressions. On the otherhand, as shown in FIG. 4, a row 202 of depressions 200 may be alignedwith an adjacent row 202 of depressions 200. It will be appreciated thatthe depressions 200 may be formed in any suitable pattern orarrangement, including geometric, random, scattered, etc. depending, forexample, upon the size and configuration of the table 10.

Desirably, the depressions 200 are formed in a predetermined patternthat minimizes the distance between the depressions. Advantageously,minimizing the distance between the depressions may minimize theunsupported areas of the opposing surface. Minimizing the distancebetween the depressions 200 may also increase the structural integrityand strength of the blow-molded plastic structure. In addition,minimizing the distance between the depressions 200 may increase thesurface smoothness of the opposing surface. Thus, for blow-moldedplastic structures such as the table 10 shown in the accompanyingfigures, the depressions 200 are desirably closely spaced on the bottomsurface 16 of the table top 12 such that the depressions are separatedby a minimum distance. This may create a table top 12 with greaterstrength and structural integrity, and the upper surface 14 of the tabletop may have increased smoothness.

Advantageously, the smaller distance between the depressions 200 mayincrease the structural integrity and strength of the blow-moldedplastic structure, which may allow the thickness of the outer wall ofthe blow-molded plastic structure to be decreased. Accordingly, lessplastic material may be used to construct the blow-molded plasticstructures because of the reduced outer wall thickness. Because lessplastic is required to construct the blow-molded plastic structure, thatmay allow the cost of the structure to be decreased. In addition, theblow-molded plastic structure may cool more quickly during themanufacturing process because of the thinner outer walls. This may allowthe blow-molded plastic structure to be removed from the mold morequickly and it may allow the structure to be removed at a highertemperature because it dissipates heat more rapidly. Significantly,these factors may decrease the cycle time required to constructblow-molded plastic structures and it may increase manufacturingefficiency.

Advantageously, increasing the number of depressions 200 and decreasingthe distance between the depressions increases the strength andstructural integrity of blow-molded plastic structures such as the tabletop 12. This is contrary to previous blow-molded plastic structureswhich required strengthening ribs to increase the strength andstructural integrity of the structures. This is also contrary toprevious blow-molded plastic structures that were created with thickerwalls to increase the strength and structural integrity of thestructures. Disadvantageously, the previously required thicker walls andstrengthening ribs required more plastic, a longer manufacturing timeand increased the weight of the structure.

In greater detail, increasing the number of depressions and decreasingthe distance between the depressions provides the surprising andunexpected result that less plastic can be used to construct theblow-molded plastic structures. Specifically, it was previously thoughtthat a larger amount of plastic would be required to increase the numberof depressions in blow-molded plastic structures. The increased numberof depressions, however, allows thinner outer walls to be used and thatallows the overall amount of plastic used to construct blow-moldedplastic structures to be decreased. Additionally, the increased numberof closely spaced depressions 200 increases the structural integrity ofthe structure, despite the fact that disruptions in the continuity ofsurface were previously thought to weaken the structure.

The depressions 200 are preferably arranged in a predetermined patternto create a structure with generally uniform characteristics. Forexample, the depressions 200 are preferably arranged in staggered rowsto decrease the distance between the depressions. Additionally, thedepressions 200 preferably have a generally constant and uniform spacingacross the surface of the structure. In particular, even if otherfeatures, objects or items are formed in the surface, the depressions200 are preferably arranged into a generally uniform and consistentpattern. Thus, one or more depressions may be formed in the otherfeatures, objects or items formed in the surface. For example, as shownin FIGS. 3 and 4, depressions 200 may be formed in the channels 160located in the bottom surface 16 of the table top 12 in order tomaintain a generally uniform and consistent pattern. In addition,depressions 200 may be spaced about these other features, objects oritems formed in the surface to keep a generally uniform and consistentpattern. Thus, the depressions are preferably spaced so that thedistance between the depressions is minimized, substantially the entiresurface is covered with depressions, and the depressions are located ina generally uniform and consistent pattern even if other features,objects or items are formed in the blow-molded plastic structure.

In order to obtain a generally uniform and consistent pattern ofdepressions, it is desirable to eliminate or minimize other features,objects or items formed in the blow-molded plastic structure.Advantageously, the generally uniform and consistent pattern ofdepressions can be more easily obtained by eliminating or minimizing theother features, objects and items in the blow-molded plastic structure.Thus, for example, strengthening ribs are preferably eliminated so thatthey do not interfere or disturb the generally uniform and consistentpattern of depressions.

As seen in FIG. 5, the depressions 200 are preferably closely spaced tominimize the distance between the depressions. In particular, thedepressions are formed in the bottom surface 16 and the depressionsextend towards the upper surface 14 of the table top 12. Each of thedepressions includes a side wall 206 and an end 210. As shown in FIG. 5,the ends 210 of the depressions 200 may contact or engage the uppersurface 14 of the table top 12. Advantageously, this may help supportthe upper surface 14 of the table top 12 and the closely spaceddepressions 200 may minimize the unsupported areas of the upper surfaceof the table top. The depressions 200 are preferably integrally formedin the table top 12 as part of a unitary, one-piece structure. Inparticular, the depressions 200 are preferably integrally formed in thetable top 12 during the blow-molding process.

The depressions 200 are preferably designed and configured to allow thedepressions to be closely spaced. In particular, the side walls 206 ofthe depressions 200 are preferably formed at a steep angle to allow thedepressions to be closely spaced. For example, the side walls 206 of thedepressions 200 are preferably at an angle between about 60° and about85° relative to the lower surface 16 of the table top 12. Morepreferably, the side walls 206 are positioned at an angle of 75° orgreater with respect to the lower surface 16 of the table top 12. Itwill be appreciated that the side walls 206 may be positioned at anydesired angle relative to the lower surface 16 of the table top 12depending, for example, upon the configuration of the depressions 200formed in the table top 12.

As seen in FIG. 5, the depressions 200 may have a height h generallyequal to a thickness t of the table top 12, where the thickness is thedistance separating the lower surface 16 and the upper surface 14. Whenthe depressions 200 have a height h generally equal to the thickness tof the table top 12, the ends 210 of the depressions desirably contactor engage the upper surface 14 of the table top at a contact area 208.It will be appreciated that the size of the contact area 208 may vary,for example, upon the shape and configuration of the depression 200. Inaddition, as shown in FIG. 5, the depressions 200 are separated by adistance d. The distance d is preferably measured from the center of onedepression 200 to the center of another adjacent depression. Desirably,the distance d separating adjacent depressions 200 is generallyconsistent so that a pattern of depressions with generally uniform andconstant spacing is create.

When the depressions 200 contact or engage the upper surface 14 of thetable top 12 as shown in FIG. 5, there is a possibility that thedepressions may create visual marks on the upper surface. In order todecrease or eliminate the marks, the thickness of the upper surface 14may be increased or decreased, the distance between depressions 200 maybe increased or decreased, the upper surface may be textured or colored,or a design, pattern or decal may be attached to the upper surface.

Additionally, in order to prevent marks from being formed in the uppersurface 14, the ends of the depressions 200 may be disposed adjacent toor spaced apart from the upper surface. For example, shown in FIG. 5A,the depressions 200 may be formed such that the ends 210 are disposedadjacent to the upper surface 14. Desirably, in this configuration, theends 210 of the depressions 200 may be adjacent to and may contact withthe upper surface 14, but the ends of the depressions are not bonded tothe upper surface. Thus, the depressions may support to the uppersurface 14, but without creating marks in the upper surface.

As shown in FIG. 6, the ends 210 of the depressions 200 do not have tocontact or engage the upper surface 14 of the table top 12. For example,the ends 210 of the depressions 200 may be spaced apart from the uppersurface 14 of the table top 12. Thus, the height h of depressions 200 isless than the thickness t of the table top 12.

As shown in FIG. 6A, when a force F is applied to the upper surface 14and the ends 210 of the depressions 200 are spaced apart from the uppersurface, the upper surface may bend, flex or deflect to ward, the lowersurface 16. If a sufficient force is applied to the upper surface 14,then the upper surface will contact the ends 210 of the depressions 200,which may prevent the upper surface from bending, flexing or deflectinga greater amount. Advantageously, this may create a blow-moldedstructure with some flexibility or “give.” This may allow, for example,a chair constructed with a blow-molded plastic seat and/or back to flexor “give” slightly when a person sits on the chair. Advantageously, thismay increase the comfort of the chair.

Accordingly, the depressions 200 may be formed such that the ends 210 ofthe depressions engage and are bonded to the opposing surface. Inaddition, the depressions 200 may be formed such that the ends 210 ofthe depressions contact, are positioned adjacent to or are spaced apartfrom the opposing surface. Advantageously, this may minimize or preventmarks, surface imperfections and/or irregularities from being formed inthe opposing surface. Further, this may improve the appearance and/orcontinuity of the opposing surface.

Additionally, one or more of the depressions 200 may be formed in otherfeatures formed in the blow-molded plastic structure such as thechannels 160 that may be formed in the lower surface 16 of the table top12. The height h of the depressions 200 formed in the channel 160 is thedistance from the plane containing the lower surface 16 of the table top12 to the ends 210 of the depressions.

As shown in FIG. 5, for example, the table top 12 may have a thickness tof about 1.0 inches. Accordingly, the depressions 210 would have aheight h of about 1.0 inches because the depressions extend from thelower surface 16 to the upper surface 14 of the table top 12. On theother hand, if the table top 12 shown in FIG. 6 has a thickness t ofabout 1.5 inches, then the depressions 210 would have a height h of lessthan about 1.5 inches, such as about 1.0 inches.

As discussed above, the distance d separating the depressions 200 ispreferably minimized and the depressions are preferably located in agenerally uniform and consistent arrangement so that the table top 12 isa lightweight, high-strength structure with relatively uniformproperties. In particular, the depressions 200 are preferably arrangedin a tightly packed array that covers substantially all the lowersurface 16 of the table top 12. For example, in order to create atightly packed array of depressions 200, the distance d between adjacentdepressions is preferably less than or equal to three times thethickness t of the table top 12, as shown in FIG. 7. In order to createa more tightly packed array of depression 200, the distance d betweenadjacent depressions is preferably less than or equal to two times thethickness t of the table top 12. The distance d between adjacentdepressions 200 may also be equal to or less than the thickness t of thetable top 12. Additionally, the distance d between adjacent depressions200 may be less than or equal to three times the height h of the tabletop 12. Further, the distance d between adjacent depressions may be twoor less times than the height h of the table top 12. Finally, thedistance d between adjacent depressions may be equal to or less than theheight h of the table top 12.

As discussed above, previous blow-molded plastic structures oftenincorporated one or more reinforcing ribs or beams to provide increasedstrength and support for blow-molded plastic structures such as tabletop 12. The foregoing description, however, provides for the surprisingand unexpected result that an increased number of depressions that areclosely spaced together creates a stronger and lighter weight table top12. Preferably, the depressions are consistently spaced oversubstantially all the entire surface of table top 12 so thatsubstantially the entire surface of table top 12 is provided withincreased strength and structural integrity. Desirably, any reinforcingribs or beams are eliminated so that the depressions can coversubstantially the entire surface. It will be appreciated, however, thatonly a portion of the table top 12 may have a plurality of closelyspaced depressions in order to provide increased structural strength toonly those particular portions of table top 12.

The increased number of closely spaced depressions may also allowblow-molded plastic structures to be created with a smoother, moreplanar outer surface. Advantageously, the more planar surface may beused to create a number of suitable objects such as the table topsdescribed above.

As shown in FIG. 8, a basketball backboard 250 may be constructed from ablow-molded plastic and it may be constructed with an increased numberof depressions that are spaced closely together to create a backboardwith increased strength and structural integrity. In addition, thebasketball backboard 250 may be constructed with a thinner outer wall,which decreases the amount of plastic required to construct thebackboard. The thinner outer wall may also allow the backboard to beconstructed more rapidly because it may be removed from the mold morequickly and at a higher temperature.

The backboard 250 is preferably a unitary structure with a top rail 252,a bottom rail 254, a first side rail 256 and a second side rail 258. Thebackboard 250 also includes a support structure 260 disposed between therails 252, 254, 256, 258. The support structure 260 desirably has agenerally H-shaped configuration with a first vertical rail 262, asecond vertical rail 264 and a horizontal rail 266. The backboard 250desirably includes a plurality of depressions 200 formed in each of therails 252, 254, 256, 258, 262, 264, 266. It will be understood thatwhile the depressions 200 can be formed in any desired portions of thebackboard 250, the depressions are preferably formed in substantiallyall of the structural portions of the backboard.

The depressions 200 are preferably formed in a rear surface 268 of thebackboard 250 so that they are not visible while playing basketball. Thedepressions 200, however, may be formed in any suitable portions of thebackboard 250. In addition, the depressions 200 may be formed on boththe front surface 270 and the rear surface of the backboard 268. As seenin FIG. 9, the depressions 200 formed in the front surface 270 and rearsurface 268 of the frame 250 are preferably generally aligned and theends of the depressions are preferably in contact or engaged. It will beappreciated that the ends of the depressions 200 could also be spacedapart and the depressions do not have to be aligned.

The present invention may be embodied in other specific forms withoutdeparting from its spirit or essential characteristics. The describedembodiments are to be considered in all respects only as illustrativeand not restrictive. The scope of invention is, therefore, indicated byappended claims rather than by foregoing description. All changes whichcome within meaning and range of equivalency of claims are to beembraced within their scope.

1. A table top constructed from blow-molded plastic including a hollowinterior portion formed during the blow-molding process, the table topcomprising: a first surface; a second surface that is disposed generallyparallel to and spaced apart from the first surface, the first surfacebeing separated from the second surface by a distance, the first andsecond surfaces enclosing at least a portion of the hollow interiorportion formed during the blow-molding process; and a plurality ofdepressions formed in the second surface and extending towards the firstsurface, each of the plurality of depressions including a sidewall andan end, each of the plurality of depressions having a height measuredfrom the second surface to the end of the depression, the plurality ofdepressions being arranged into a predetermined pattern that covers atleast a majority of the lower surface, a majority of the plurality ofdepressions having a generally uniform configuration and a generallyconsistent distance between adjacent depressions, the distanceseparating adjacent depressions being approximately equal to or lessthan three times the average height of depressions, the height of theplurality of depressions being less than or equal to the distanceseparating the first surface and the second surface.
 2. The blow-moldedplastic table top as in claim 1, wherein the end of at least a majorityof the plurality of depressions is spaced apart from the first surface.3. The blow-molded plastic table top as in claim 1, wherein the sidewallof each of the plurality of depressions is at an angle between about 60°and about 85° relative to the second surface.
 4. The blow-molded plastictable top as in claim 1, wherein the plurality of depressions coversubstantially the entire second surface.
 5. The blow-molded plastictable top as in claim 1, wherein the plurality of depressions allow athickness of the first surface and the second surface to be decreased.6. The blow-molded plastic table top as in claim 1, wherein theplurality of depressions have a generally uniform and consistent spacingacross substantially all the second surface of the blow-molded plastictable top.
 7. The blow-molded plastic table top as in claim 1, whereinthe plurality of depressions have a generally uniform and consistentspacing across substantially all the second surface of the blow-moldedplastic structure so that the depressions are sized and configured tosupport the first surface in a generally consistent manner so that theblow-molded plastic table top has generally uniform strength andstructural integrity.
 8. The blow-molded plastic table top as in claim1, further comprising at least one channel disposed in the secondsurface, the channel including a height that is less than the distanceseparating the first surface from the second surface.
 9. The blow-moldedplastic table top as in claim 8, further comprising a portion of theplurality of depressions being at least partially disposed in thechannel.
 10. The blow-molded plastic table top as in claim 1, whereinthe end of at least a majority of the plurality of depressions contactsthe first surface.
 11. The blow-molded plastic table top as in claim 1,wherein the plurality of depressions are integrally formed in theblow-molded plastic structure as part of a unitary, one-piece structure;and wherein the plurality of depressions have a generally circular oroval configuration to allow the depressions to be closely spaced.
 12. Atable comprising: a table top constructed from blow-molded plastic andincluding a generally hollow interior portion that is formed during theblow-molding process, the table top including an upper surface, a lowersurface and a thickness measured from the upper surface to the lowersurface; a plurality of depressions integrally formed in the lowersurface of the table top as part of a unitary, one-piece structure, theplurality of depressions being arranged into a predetermined patternthat covers at least a majority of the lower surface of the table top, amajority of the plurality of depressions having a generally uniformconfiguration and a generally consistent distance between adjacentdepressions, the plurality of depressions being sized and configured toincrease the strength of the table top, the plurality of depressionsincluding a height measured from the lower surface to an end of thedepression, each adjacent depression of the plurality of depressionsbeing separated by a distance that is generally equal to or less thanthree times the average height of the plurality of depressions; and asupport structure that is connected to the table top to support thetable top above a surface.
 13. The table as in claim 12, wherein the endof at least a majority of the plurality of depressions is disposedadjacent to the upper surface of the table top.
 14. The table as inclaim 12, wherein the end of at least a majority of the plurality ofdepressions is spaced apart from the upper surface of the table top. 15.The table as in claim 12, wherein each of the plurality of depressionshas a sidewall that is at an angle of at least about 75° with respect tothe lower surface.
 16. The table as in claim 12, wherein the pluralityof depressions cover substantially the entire lower surface of the tabletop.
 17. The table as in claim 12, wherein the plurality of depressionshave a generally uniform and consistent spacing across substantially allthe lower surface of the table top so that the depressions are sized andconfigured to support the upper surface in a generally consistent mannerso that the table top has generally uniform strength and structuralintegrity.
 18. A table comprising: a table top constructed fromblow-molded plastic and including a generally hollow interior formedduring the blow-molding process, the table top including an uppersurface, a lower surface and a thickness measured from the upper surfaceto the lower surface; a plurality of depressions integrally formed inthe lower surface of the table top as part of a unitary, one-piecestructure, the plurality of depressions being arranged into apredetermined pattern that covers at least a majority of the lowersurface of the table top, a majority of the plurality of depressionshaving a generally uniform configuration and a generally consistentdistance between adjacent depressions, each of the plurality ofdepressions having a height measured from the lower surface to an end ofthe depression, each adjacent depression of the plurality of depressionsbeing separated by a distance that is generally equal to or less thanthree times the average height of the plurality of depressions; and asupport structure that is connected to the table top to support thetable top above a surface.
 19. A table top constructed from blow-moldedplastic including a hollow interior portion formed during theblow-molding process, the table top comprising: a first surface; asecond surface that is disposed generally parallel to and spaced apartfrom the first surface, the first surface being separated from thesecond surface by a distance, the first and second surfaces enclosing atleast a portion of the hollow interior portion formed during theblow-molding process; and a plurality of depressions formed in thesecond surface and extending towards the first surface, each of theplurality of depressions including a sidewall and an end, each of theplurality of depressions having a height measured from the secondsurface to the end of the depression, the plurality of depressions beingarranged into a predetermined pattern that covers at least a majority ofthe lower surface, a majority of the plurality of depressions having agenerally uniform configuration and a generally consistent distancebetween adjacent depressions, the distance separating adjacentdepressions being approximately equal to or less than two times theaverage height of the plurality of depressions, the height of theplurality of depressions being less than or equal to the distanceseparating the first surface and the second surface.
 20. A table topconstructed from blow-molded plastic including a hollow interior portionformed during the blow-molding process, the table top comprising: afirst surface; a second surface that is disposed generally parallel toand spaced apart from the first surface, the first surface beingseparated from the second surface by a distance, the first and secondsurfaces enclosing at least a portion of the hollow interior portionformed during the blow-molding process; and a plurality of depressionsformed in the second surface and extending towards the first surface,each of the plurality of depressions including a sidewall and an end,each of the plurality of depressions having a height measured from thesecond surface to the end of the depression, the plurality ofdepressions being arranged into a predetermined pattern that covers atleast a majority of the lower surface, a majority of the plurality ofdepressions having a generally uniform configuration and a generallyconsistent distance between adjacent depressions, the distanceseparating adjacent depressions being approximately equal to or lessthan the average height of the plurality of depressions, the height ofthe plurality of depressions being less than or equal to the distanceseparating the first surface and the second surface.
 21. A tablecomprising: a table top constructed from blow-molded plastic andincluding a generally hollow interior portion that is formed during theblow-molding process, the table top including an upper surface, a lowersurface and a thickness measured from the upper surface to the lowersurface; a plurality of depressions integrally formed in the lowersurface of the table top as part of a unitary, one-piece structure, theplurality of depressions being arranged into a predetermined patternthat covers at least a majority of the lower surface of the table top, amajority of the plurality of depressions having a generally uniformconfiguration and a generally consistent distance between adjacentdepressions, the plurality of depressions being sized and configured toincrease the strength of the table top, the plurality of depressionsincluding a height measured from the lower surface to an end of thedepression, each adjacent depression of the plurality of depressionsbeing separated by a distance that is generally equal to or less thantwo times the average height of the plurality of depressions; and asupport structure that is connected to the table top to support thetable top above a surface.
 22. A table comprising: a table topconstructed from blow-molded plastic and including a generally hollowinterior portion that is formed during the blow-molding process, thetable top including an upper surface, a lower surface and a thicknessmeasured from the upper surface to the lower surface; a plurality ofdepressions integrally, formed in the lower surface of the table top aspart of a unitary, one-piece structure, the plurality of depressionsbeing arranged into a predetermined pattern that covers at least amajority of the lower surface of the table top, a majority of theplurality of depressions having a generally uniform configuration and agenerally consistent distance between adjacent depressions, theplurality of depressions being sized and configured to increase thestrength of the table top, the plurality of depressions including aheight measured from the lower surface to an end of the depression, eachadjacent depression of the plurality of depressions being separated by adistance that is generally equal to or less than the average height ofthe plurality of depressions; and a support structure that is connectedto the table top to support the table top above a surface.
 23. A tablecomprising: a table top constructed from blow-molded plastic andincluding a generally hollow interior formed during the blow-moldingprocess, the table top including an upper surface, a lower surface and athickness measured from the upper surface to the lower surface; aplurality of depressions integrally formed in the lower surface of thetable top as part of a unitary, one-piece structure, the plurality ofdepressions being arranged into a predetermined pattern that covers atleast a majority of the lower surface of the table top, a majority ofthe plurality of depressions having a generally uniform configurationand a generally consistent distance between adjacent depressions, eachof the plurality of depressions having a height generally measured fromthe lower surface to an end of the depression, each adjacent depressionof the plurality of depressions being separated by a distance that isgenerally equal to or less than two times the average height of theplurality of depressions; and a support structure that is connected tothe table top to support the table top above a surface.
 24. A tablecomprising: a table top constructed from blow-molded plastic andincluding a generally hollow interior formed during the blow-moldingprocess, the table top including an upper surface, a lower surface and athickness measured from the upper surface to the lower surface; aplurality of depressions integrally formed in the lower surface of thetable top as part of a unitary, one-piece structure, the plurality ofdepressions being arranged into a predetermined pattern that covers atleast a majority of the lower surface of the table top, a majority ofthe plurality of depressions having a generally uniform configurationand a generally consistent distance between adjacent depressions, eachof the plurality of depressions having a height generally measured fromthe lower surface to an end of the depression, each adjacent depressionof the plurality of depressions being separated by a distance that isgenerally equal to or less than the average height of the plurality ofdepressions; and a support structure that is connected to the table topto support the table top above a surface.